Playground structure



Feb. 20, 1962 c. G. BASSETT 3,022,036

PLAYGROUND STRUCTURE Filed Aug. 12, 1959 ATTORNEYS.

United States Patent O 3,022,036 PLAYGROUND STRUCTURE Cleveland G. Bassett, Urbana, Ill. (673 Craig Woods Drive, Kirkwood 22, Mo.) Filed Aug. 12, 1959, Ser. No. 833,279 2 Claims. (Cl. 248-402) This invention relates to a playground structure, and more specifically, to a spring-equipped stool particularly suited for use by childern as a playground amusement device.

An object of the present invention is to provide a simple, durable and relatively inexpensive structure which may be fixed in a selected location in a play area for the amusement of children. Another object is to provide an amusement device upon which, children may climb and jump and which is helpful in assisting children to develop balance and agility. Other objects will appear from the specification and drawings in which:

FIGURE *1 is a perspective view of a structure embodying the present invention; and

FIGURE 2 is an enlarged vertical cross-sectional view showing structural details of the spring-equipped stool.

In the embodiment of the invention illustrated in the drawings, the numeral generally designates a stool adapted to be situated in a playground or other play area for use as an amusement device by children. When the unit is completely installed, as indicated in FIGURE 1, it has the general appearance of a large toadstool, the stool having an enlarged top 11 and a vertical central column or stem 12.

Referring to FIGURE 2, it will be seen that the stool consists essentially of the flat top member 11, the vertical column 12, a vertical tube 13 and a heavy coil spring 14. The enlarged tube 13 is disposed vertically beneath the ground level and is preferably embedded in a concrete foundation 15. Preferably, tube 13 is provided at its bottom with a closure plate 16 which may be welded or otherwise secured to the tube. At its upper end, the tube is externally threaded and is received by an internally threaded annular collar 17 equipped at its top with an annular retaining plate or ring 18. Plate 18 serves as a stop to limit both upward and downward movement of the central column and top assembly, as will be evident from the following description, and holds a resilient annular gasket 19 firmly in place between its undersurfa'ce and the upper end of tube 13. It will be noted that the diameter of the opening defined by gasket 19 is slightly smaller than the opening defined by annular plate 18 directly thereabove.

The vertical column or stem 12 is tubular in construction and is telescopingly received by the embedded tube 13 through the open upper end thereof. The column has an external diameter substantially smaller than the internal diameter of tube 13 but of approximately the same diameter as the opening defined by annular gasket 19. Thus, while the column is freely slidable in vertical directions through the openings provided by gasket 19 and plate 18, these latter elements cover the space between column 12 and tube 13 at the upper end of the tube and thereby tend to prevent rain, snow and dirt from falling downwardly into the interior of the embedded tube.

At its lower end, the tubular column 12 is provided with a circular bottom plate 20 which is welded or otherwise secured thereto. The diameter of the bottom plate is greater than the internal diameter of the opening defined by gasket 19 and ring 18 so that upward movement of the column will be limited by engagement between the undersurface of the gasket or cushion 19 and the upper surface of the peripheral portion of the plate 20 which projects laterally beyond the outer surface of the column. However, as shown in FIGURE 2, the diameter of plate 20 is suiiiciently less than the internal diameter of tube 13 to and which extends downwardlyand inwardly about the.

tubular ring. The cover may be formed from rubber or any other tough resilient plastic material and has a tread or ribs formed in its upper surface to prevent slipping by a person whose weight is sunnortedby the stool. Annulus'24 is welded or firmly attached by other appropriate means to both the undersurface of disk 21 and the outer surface of column 12 adjacent the upper end thereof. This annulus not only reinforces the connection between the column 12 and'top' 11 but also provides a firm backing for the annular cushion 25 disposed directly therebelow. Like gasket 19, cushion 25 maybe formed from rubber or from any materialhaving the necessary i qualities of resiliency and durability.

Coils pring 14 is disposed within tube: 13 between bot tom plate 16 and plate 20 at the'bottom of column 12. The ends of the spring are preferably welded or otherwise secured to both of these plates, although either or both ends may, if desired, be left unattached to the respec-' tive plates. In FIGURE 2, spring 14 is shown in a neutral condition; that is, it is neither in a state of expansion or in a condition of compression except, of course, for the slight compression resulting from the weight of the column and top assembly imposed on it. Thus, it will be observed that when the spring is in a substantially neutral condition its axial length is approximately one-half the length of the embedded tube 13. In other Words, when the spring-equipped stool is in a state of rest, the bottom end of column 12 is disposed substantially intermediate the upper and lower ends of tube 13. As a result, the column and top assembly is free to move upwardly as well as downwardly from the position illustrated in the drawings.

Column 12 may be of any reasonable length and, if desired, a number of stool assemblies may be grouped together in a playground area, the column length of each stool being different so that children may climb or jump from one stool to another.

It is believed apparent that when a child climbs or jumps upon the flat top of a stool of the character illustrated in the drawings, the column and top assembly will move downwardly from the position shown in FIGURE 2. If a child jumps upon the stool, thereby supplying a downward force in excess of his actual weight, the column and top assembly will first move downwardly and will then spring upwardly, frequently beyond the neutral point illustrated in the drawings, by reason of the force exerted by coil spring 14. Thus, a child may bounce up and down upon the stool, the column and top assembly moving alternately in opposite vertical directions from the position shown. A variety of games may be played with the stool or with a group of stools, the particular game depending largely upon the age of the children and their imagination, coordination and balance.

Excessive vertical movement of the column and top is limited by stop ring 18 and gasket 19, the gasket engaging plate 20 when the column reaches the upper limit of its movement and the stop ring 18 engaging cushion 25 when the top 11 is fully depressed. The resilient nature of the gasket and cushion eliminate the sharp jolts which might otherwise occur upon extreme vertical movement of the column and top assembly.

While in the foregoing I have disclosed an embodivertical first tube fixed in place beneath a ground surface and being open at its upper end, a second tube telescopinglyv and slidably received in said first tube and projecting upwardly beyond the upper end of saidfirst tube, a, single coil spring vertically disposed within said first tube and having its lower end fixedv against downward movement with reference thereto, said spring when in neutral condition having itscoils spaced apart to permit both axial compression and expansion thereof, Said second tube having itslower endinengagement with the upper end of said spring and having said lower end di sposed"substantially intermediate the upper and lower ends of said first tube when said spring" is in a neutral condition, said second tube being of substantially smaller external diameter thanthe internal diameterof said first tube to provide an annular spacing therebetween for the free flow of air between opposite ends of said firsttube and about the periphery of saidfsecond tube as said' sec ond tube travels upwardly and downwardly, and a'flat horizontal top member liked to the upper end of said second tube and having horizontal dimensions substantially greater than said tubes, whereby, said second tube may travel upwardly and downwardly in response to forces imposed upon said top member without appreciable resistance to such movement from the flow of air through said first tube.

2. The structure of claim 1 in which said first tube is closed at the bottom thereof, said spring having its lower end secured to the bottom of said first tube and having its upper end secured to the bottom of said second tube, the attachment of said spring to said tubes being unafiected by upward and downward movementrof said second tube.

References Cited in the file of this patent UNITED STATES PATENTS 966,745 Hileman Aug. 9, 1910 1,400,974 Parker -2 Dec. 20, 1921 2,092,669 Grere -Sept. 7, 1937 2,266,268 Robinson Dec. 16, 1941 2,526,552 Gillespie Oct. 17, 1950 2,619,154 Erickson Nov. 25, '1952 2,628,142 Dubach Feb-10, 1953 2,664,941 Gillespie Jan. 5, 1954 2,739,857 Fisher et a1. Q Mar-127', 1956 2,788,842 Ohlenkamp Apr. 16, 1957 2,792,268.

Stanley May 14, 1957 

